Explanation:

- Margaret Atwood is the author of 'The Testaments'. This book is a sequel to her famous novel, 'The Handmaid's Tale'. Published in 2019, it won the Booker Prize.

- Jokha Alharthi is an Omani author known for her novel 'Celestial Bodies', which won the Man Booker International Prize in 2019.

- Andrew Sean Greer wrote 'Less', a comedic novel that won the Pulitzer Prize for Fiction in 2018.

- Anna Burns is known for her novel 'Milkman', which won the Man Booker Prize in 2018.

Your answer is right. Margaret Atwood is indeed the author of 'The Testaments'.